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Acmaeodera immaculata is a highly variable species, Horn (1878), illustrated 6 "variants" of A. pulchella in his treatment of the genus, including A. pulchella immaculata. Bright (1987) in his treatment of the Canadian species recognized two species in Alberta, A. pulchella and A.variegata. He placed most specimens in A. variegata. I believe this to be incorrect. On examination of A. variegata specimens from Utah, these beetles bear very little resemblance except for colour pattern. Differences include, the shape of the prosternum (which places variegata in Horn's group Acmaeoderae emarginatae and pulchella in Acmaeoderae truncatae), shape and sculpture of pronotum (variegata has two lateral and one medial basal depression, all well developed, in pulchella these are lacking or faintly present, the elytra on specimens of variegata is flattened, where as in pulchella it is more evenly convex). All specimens thus far examined are placed in the species Acmaeodera immaculata. Additional biological evidence supports beetles of A. immaculata as distinct from those of A. pulchella comes from known host associations. Baker (1972) reports A. pulchella beetles breeding in bald cypress in the southern and eastern states. Dying and freshly cut cypress may be subject to severe attack. Barr (1971) reports larvae of A. immaculata feeding on roots of of winter fat (Eurotia lanata (Pursh)). Adult Acmaeodera beetles in Alberta have been collected in close proximity to winter fat (1 to 2 meteres) while feeding on pollen in nearby flowers. No other trees or shrubs were within 0.5 km.

Reported to feed on Erotia lanata in Idaho. This species of plant is wide spread, in the grasslands of Alberta and adult Acmaeodera beetles have been collected in close proximity. Barr (1971) reports adults on flowers of Opuntia spp. and Sphaerlacea spp. (mallow).